Several days ago US Secretary of State John Kerry announced a significant shift in the US approach to the ongoing Syrian civil war, following Kerry's Moscow meetings with Russian Minister of Foreign Affairs Sergey Lavrov and Russian President Vladimir Putin.
"The United States and our partners are not seeking so-called regime change," Kerry told the media.
The shift was considered to pave the way for the adoption of a UN Security Council Resolution calling for a ceasefire and a political resolution to the devastating war in Syria.
But, the analyst noted, during an annual press conference President Obama announced a completely different direction for US foreign policy, leaving his Secretary of State "and [the] entire foreign policy apparatus" without presidential support.
"No, Obama decided this afternoon, Assad cannot stay. Assad must go." McAdams wrote on December 18.
The UN Security Council on Friday unanimously approved a plan on the peaceful settlement of the Syrian civil war. In its resolution the council asks the United Nations Secretary-General Ban Ki-Moon via Special Envoy of the Secretary-General for Syria, Staffan de Mistura, to urgently summon representatives of the Syrian government and opposition for formal negotiations on a political transition in the country in January 2016.